The present invention relates to a micro-article processing system with an optical pattern, and more specifically to a micro-article processing system comprising a detector for detecting a shift of a micro-article and a device for performing prescribed processing independently of any shift of said micro-article by being shifted by a signal from said detector in such a manner as to compensate the shift.
In various fields of the art, a number of micro-articles are fed continuously to detect the shift of every individual article from the prescribed position thereof, and then a device in a subsequent process is shifted in response to said shift, thereby accomplishing desired operations. As a distinguished embodiment of such system is known a wire-bonding system for semiconductor pellets, which will be described hereinafter.
In a manufacturing process for some kinds of semiconductor elements, a pellet is attached to a lead frame and a fine wire is bonded to a specified area defined by a pattern formed on the surface of said pellet.
In this case, attaching of a pellet to said lead frame is generally accompanied by a substantial shift. Accordingly, in order to accomplish precise bonding, it is essential to provide a bonding device capable of detecting the shift of pellet correctly and performing bonding operation corresponding to such shift.
In the prior art, detection of said shift is performed by detecting a pattern formed on the surface of the pellet by an electrooptical method or by detecting a special detection mark previously formed on a pellet as a datum point. In general, the pattern on the surface of the pellet is both complicated and fine, so that the latter method in which a special mark is formed on a pellet is not preferable because it will place additional restrictions on the space for the complicated and fine pattern essential to a pellet. Meanwhile, as for the former method in which the entire pattern essential to the pellet is utilized, it is difficult to pick out a pattern required for detection out of complicated and fine patterns. Further, the patterns on the surface of any pellets generally vary with the types of pellets, so that it is also difficult to utilize such patterns for location of all these types of pellet. Thus such method is applicable to specific patterns only and may not be able to establish correct and easy detection of location.